Arrangement of switching appliances in connection with telephones.



Patented Ian. 29, IBM.

P. RABBIDGE. ARRANGEMENT 0F SWITCHING APPLIANCES IN CONNECTION WITHTELEPHONES.

(Application filed Feb. 26. 1900.)

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No. 666,874. Patented Jam 29, |9OL P. RABBIDGE. ARRANGEMENT 0F SWITCHINGAPPLIANCES IN CONNECTION WITH TELEPHUNES.

(Application filed Feb. 26, 1900.

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(No Model.)

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No. 666,874. Patented Ian. 29, 190:.

P. RABBIDGE.

ARRANGEMENT 0F SWITCHING APPLIANCES IN CONNECTION WITH TELEPHONES.

, (Application filed Feb. 2a. 1900.

(No Model.) 3 ShaetsSheet 3.

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Q N f -i.... l 0 C31 Q WITNESSES:

' ATTORNSYS UNITED STATES PATENT GFFICE.

PARNELL RABBIDGE, OF SYDNEY, NEW SOUTH WALES.

ARRANGEMENT 0F SWITCHING APPLIANCES IN CONNECTION WITH TELEPHONES.

SPECIFICATION forming part of Letters Patent No. 666,874, dated January29, 1901. A

Application filed February 26, 1900. Serial NO- 63619. (No model.)

To all whom it may concern: I

Be it known that I, PARNELL RABBIDGE, a subject of the Queen of GreatBritain and Ireland, and a resident of Sydney, in the county ofCumberland and Colony of New South Wales, have invented a certain newand Improved Arrangement of Switching Appliances for Use withTelephones, of which the following is a specification.

This invention has been devised for use in connection with private ordomestic systems of telephonic intercom munication. Hitherto whenconversation is being carried on between any two points of the system ithas been usual for a third person stationed at any intermediate point inthe system to be able to switch into their line and overhear theconversation thus carriedon. It has also been usual hitherto after theinstruments have been used for conversational purposes for theselecting-switches employed to be returned to their normal position byspecial operations performed by the operators.

The objects of this invention are, first, to provide means whereby asecret system of intercommunication betweenany two points of a system oftelephonic connections may be obtained without the possibility of theconversation between such two points being overheard at any other pointin the system, and, second, to provide means whereby the telephonicinstruments after they have been used for conversational purposes may beautomatically restored to a position in which they may be able toreceive a call from any of the other stations connected therewith.

The special feature of the invention consists in the employment of aparticular form of switching appliance thatisintroducedinto the circuitbetween the selecting-switchboard and the instrument. This switchingappliance is so arranged and constructed that when a certain portion ofthe appliance is in its lowest position the station to which it isconnected may receive a call from any one of the other stations of thesystem. When in its highest position, a call may be sent from thestation to which it is connected to any one of the other stations, andwhen placed in its middleposition at each of two stations connected witheach other conversation between such stations may be carried on withoutbeing overheard at any of the other sta tions of the system. Thisswitching appliance is also so constructed that when a conversation isfinished and the telephonic instrument at the calling station is hungupon its hook the switch is automaticallyreplaced in a position forreceiving a call from any of the other stations.

I will describe the invention in relation to a form of instrument thatis operated by means of a gravity-switch contained within inself.

In order that the invention may be thoroughly understood, reference ismade to the accompanying sheet of drawings, in which- Figure 1 is adiagrammatic view of the circuits and switches used in connection with asystem that is operated from three stations. Fig. 2 is a back elevationof the special form of switching appliances used in connection with thisinvention. Fig. 3 is a transverse vertical section of the same. Fig. 4is aside elevation, partly in section, of one form of telephonicinstrument that may be used in connection with this invention. Fig. 5 isa part plan of the same with the top cover removed. Fig. 6 is a modifiedform of the appliance shown in Fig. 2. Fig. 7 is a diagrammatic view ofthe circuits of the switch ing appliances and general working circuitsof two stations, the difierent circuits being shown in position forconversation between the two stations.

Referring now to Figs. 2 and 3, A is a box or cover, in which arecontained the switching appliances hereinbefore referred to. Theseswitching appliances consist of four spring-metal connecting-pieces B BB B secured to the box. Behind these connectingpieces and impingingagainst them are two studs 0 O, which are connected to a sliding block0, which slides up and down in a groove 0 in the front of the boX. Tothefront of the sliding block is attached a hook or knob 0 By sliding theblock up and down in its groove the studs 0 C may be brought,respectively, into contact with either the connecting-pieces B and B, Band B or B and B The stud O is connected through the wire D with one poof the battery J, used for working the telephon The other stud O isconnected through the with the telephonic instrument. The fourconnecting-pieces B B B B are connected by means of the wires b 1212 brespectively, as follows: B is connected with the line-selector plug, 13with earth, B with earth, and B with the home-line wire, as shown inFig. 7.

The telephonic instrument shown in Figs. 4 and 5 consists of theordinary form of combined receiver and transmitter, but provided with anautomatic switch in the handle, by which the call bell or instrument maybe placed in or out of circuit. This switch consists of a long narrowpiece of metal E, that is let into the back of the instrument andprojects out beyond the receiver end. This end is provided with an eye'10, which is made large enough to fit over the hook or knob c of theswitching appliance A. The other end of the metal piece E is secured bymeans of a helical spring E to the frame of the instrument. Secured toand near this end of the metal rod E is aprojecting piece 6, whichprojects upward through a slot F in the handle of the instrument. Ateach end of the slot F is placed a spring contact'piece ff, with whichthe projecting piece 0 of the metal rod E will form a metallicconnection when the rod is pulled out or drawn in. When the instrumentis hung by means of the eye at the end of the rod E upon the hook orknob 0 the rod E will be drawn out, so that the projecting piece c willform contact with the spring contact-piece f. Then the weight of theinstrument is taken off the hook, the spring E will draw back the metalrod E, so that the projecting piece 6 will form contact with the springcontact-piece f. Placed near one end of the slot F and on each side ofthe spring contact-piecefare metal knobs G G, the purposes of which willbe hereinafter explained. Placed above these two knobs is a spring-plateK, which may be pressed downward by means of the button is, so as toimpinge upon both knobs and connect them together.

The telephonic instrument is connected with the switching appliances Ain the following manner: The wire D, leading from the stud O, isconnected to the helical spring E and through it to the metal rod E. Thewire H, leading from the bell H, is connected to the contact-piece f.The metal knob G is connected by means of the wire J with the other poleof the battery Jto that to which the rod 0 is connected. From thecontact-piece f a wire L is led and passes through both poles of thetransmitter, then through the receiver, and back to the knob G. A wire Malso connects the spring contact-piece f with the knob G.

The manner of working the appliances is as follows: Referring to Fig. l,in which No. 1 station is shown as calling up No. 3 station, theoperator will remove his instrument from the hook C as shown in thediagram, when the spring-switch within it will be drawn down and makecontact with the spring-piece f, as shown in Figs. 4 and 5. He will thenplace the plug connected to the wire I) of the switching appliance A inthe hole connected with No. 3 wire and push the knob c and sliding block0 up to their highest position, when the studs 0 and G will form contactwith the connecting-pieces B and B, respectively. He will then pressdown the springpush 7t and plate K in the instrument, Fig. 4c, andconnect the two knobs G and G together. This will have the eifect ofsending the current from the negative pole of the battery through thewire J to the knob G, from whence it will travel across the springplateK to the knob G, through the wire M, to the contact-piece f, from thereto the projection e of the metal piece E, through the spring E, wire D,to the stud 0, through the connecting-piece B, and wire I) to the earthterminal N. The current from the positive pole of the battery willtravel through the wire D to the stud O through the contactpiece B andwire 1) and its plug to the wire No.3, and will enterthe correspondingswitching appliance at No. 3 station through the wire I) to theconnecting-piece B and from thence through the red C, (the instrument ofNo. 3 being hung upon its book and the metal piece E being drawn out,)wire D, connected with it, to the spring E and metal piece E, to thespring contact-pieeef, through the wire H to the bell H, (causing it tosound,) and then to the earth terminal N. \Vhen the operator at No. 3station removes his instrument from the hook, (the hook or knob 0 beingleft in its lowest position,) the metal piece E will be drawn into theposition shown in Figs. 3 and 4 and the current passing in from thepositive pole of No. 1 station will take the following course: throughthe wire b connecting-piece B red 0, wire D, spring E, metal piece E tothe spring contact-piece f, from thence through the transmitter andreceiver by means of the wire L to the knob G and through the wire J tothe negative pole of the battery, while the current from the positivepole of his battery will pass through the wire D,con necting-piece B andwire I) to the earth terminal N. The operator at No. 1 station willremove the pressure from the spring-push 7c, and the current from hisbattery will then be divided and pass through his instrument in the samemanner as the current passes through the instrument at No. 3 station. Itwill thus be noted that the batteries at Nos. 1 and 3 stations areplaced in series with each other. Both instruments will now be in aposition for conversation. When the conversation has been finished, theinstruments will be hung upon their respective hooks and the metal pieceE drawn out. The weight of the instrument at No. 1 station will have theeffect of drawing down the sliding block 0, and with it the studs 0 andC, so that they may assume their normal position (shown in Figs. 2 and3) and the instrument be placed so that a call may be received. It willthus be ICC seen that the act of restoring the switches to positionssuch that a call may be received from any one of the stations in thesystem of connections is entirely automatic, being dependent only on theinstruments being placed back upon their hooks. Should it be desired tocarry on a private conversation between stations 1 and 3-"6. e., to soarrange the circuits that a person at No. 2 station could not switch hisinstrument into the circuit and so overhear the conversationthefollowing operations will be carried out: The operator at No. 3 stationwill place his switch-plug in the No. 1 hole of his line-selector. Boththe operators at Nos. 1 and 3 stations will place the knob or hook c oftheir respective switching appliances at half-way up the slot 0'. Thestuds 0 and C will thus be brought respectively into contact with theconnecting-pieces B and B of each instrument. This will have the effectof cutting out the earth circuit and substituting for it a metalliccircuit. The current will then pass in the following manner: Startingfrom the positive pole of No. 1 battery it will pass through the wire D,connecting-piece B, wire I) to the line-selector, along No. 3 wire toNo. 3 station, where it will enter through 19 and pass from thencethrough the connecting-piece B stud O, and wire D through theinstrument, as before described, out to the negative pole of No. 3battery. The current from the positive pole of No. 3 battery will thenfollow the same relative course as that taken by the currentfrom No. 1battery, passing along No. 1 wire, and will connect with the negativepole of that battery.

Although I have described this invention as used in conjunction with aform of telephonic instrument in which the gravity-switch is employed,it is evident that the switching appliances may be adapted for use withany class of telephones. The different relative connections would,however, have to be made in the manner that has been herein set forthshould any other form of instrument be employed.

It is obvious that the contact-pieces B B B B instead of being made ofthe lengths shown in the drawings, Fig. 2, may be made all of onelength, as shown in Fig. 6,in which case the switch would not beapplicable to secret communication, as there would be no intermediateposition.

The form of switching appliance that has been shown in the drawings isof such construction as to be specially applicable to the class of workdesired; but any other switching appliance that is constructed upon thesame principle for the purpose of doing similar work might be adopted,the actual form of the appliance being of less moment than that itshould fulfil the conditions described.

Having now described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. In combination in a telephone system, a line-selector plug, aconnecting-piece B in connection with said plug, a connecting-piece Bconnected to earth, a connecting-piece B connected to earth, aconnecting-piece B a home-line wire to which said piece B is connected,a block carrying contacts 0 C, a battery and the telephonic instrumentand bell to which the said contacts 0, O are respectively connected, theconnecting-pieces B,B and the connecting-pieces B B being arranged to beengaged by the contacts 0, C, respectively as the block is moved,substantially as described.

2. In combination in a telephone system, a line-selector plug,aconnecting-piece B in connection with said plug, a connecting-piece Bconnected to earth, a connecting-piece B connected to earth, aconnecting-piece B a homeline wire to which said piece B is connected, ablock carrying contacts 0 O, a battery and the telephonic instrument andbell to which the said contacts 0, O are respectively connected, theconnecting-pieces B, B and the OOIIHGCIJlIlg-PIBOGS B B being arrangedto be engaged by the contacts 0, C, respectively as the block is moved,said block being arranged to be lowered to normal position with itscontacts engaging the connecting-pieces B B when the telephonicinstrument is hung up, substantially as described.

3. In combination in a telephonic system, the connecting-pieces B, Barranged side by side,- the connecting-pieces B B arranged side by side,said pieces B and B having portions side by side, a sliding block havingcontacts O O to engage either the pieces B, B, B B or B B aselector-plug connected to the piece B, the piece B being connected toearth, the piece B being connected to earth, the home-line wireconnected to the piece B the battery and the telephonic instrument andbell connected respectively to the contacts O G, substantially asdescribed.

In witness whereof I have hereunto set my hand in presence 01' twowitnesses.

PARNELL RABBIDGE.

Witnesses:

JAS. T. HUNTER, R. W. EWERS.

